On Silbury Hill by Adam Thorpe
 
Her [Silbury] base covers five acres of Wiltshire turf, the equivalent of three football pitches. Five acres that have not seen sunlight or stars for some 4,300 years and will never see sunlight again until, possibly, the ice of the next Ice Age to extend as far as southern England scratches her away like a pimple. In her day she must have been almost unimaginably colossal, since nothing else man-made came anywhere near. She was probably as white, when completed, as the dome of the Taj Mahal – not with marble, but with ungrassed chalk. To visitors seeing her for the first time, she would have seemed otherworldly, miraculous, impossibly smooth and symmetrical…
 
Adam Thorpe
 
More here. See also the review by Paul Farley in the Guardian.